Methodology

The basic principle of the erythrocyte sedimentation rate (ESR) test is that anticoagulated blood is placed in a verticle column that remains undisturbed for a specified amount of time. At the conclusion of the test, the distance the red cells have settled is measured in mm per hour (Westergren method). The MINI-CUBE is an automated ESR analyzer incorporating new technology that accurately and precisely measures the sedimentation rate of erythrocytes in standard 13 x 75 mm K₂EDTA blood collection tubes with Hemogard or conventional stoppers, or K₂EDTA microtainer tubes. The results are recorded as mm per hour in 20 minutes. The instrument compensates for temperatures above 18°C according to Manley's Nomogram and offers the ability to adjust for patient hematocrit values <40%.

Red cell sedimentation is accelerated by an increase in the plasma concentration of "acute phase proteins," which are increased in acute tissue damage, chronic inflammation, chronic infection, and pregnancy. The ESR reflects both the increase in certain accelerating proteins, such as fibrinogen and gamma globulins, and the decrease in retarding proteins, such as albumin. Conditions that promote the formation of rouleaux produce an elevated ESR result.